Study of the accretion torque during the 2014 outburst of the X-ray pulsar GRO J1744-28
Date Issued
2017
Author(s)
•
Riggio, A.
•
Burderi, L.
•
•
Di Salvo, T.
•
•
Bozzo, E.
•
Esposito, P.
•
•
Scarano, F.
•
Iaria, R.
•
Gambino, A. F.
Abstract
We present the spectral and timing analysis of the X-ray pulsar GRO J1744-28 during its 2014 outburst using data collected with the X-ray satellites Swift, INTEGRAL, Chandra, and XMM-Newton. We derived, by phase-connected timing analysis of the observed pulses, an updated set of the source ephemeris. We were also able to investigate the spin-up of the X-ray pulsar as a consequence of the accretion torque during the outburst. Relating the spin-up rate and the mass accretion rate as \dot{ν }∝ \dot{M}^{β }, we fitted the pulse phase delays obtaining a value of β = 0.96(3). Combining the results from the source spin-up frequency derivative and the flux estimation, we constrained the source distance to be between 3.4 and 4.1 kpc, assuming a disc viscous parameter α to be in the range of 0.1-1. Finally, we investigated the presence of a possible spin-down torque by adding a quadratic component to the pulse phase delay model. The marginal statistical improvement of the updated model does not allow us to firmly confirm the presence of this component.
Volume
469
Issue
1
Start page
2
Issn Identifier
0035-8711
Ads BibCode
2017MNRAS.469....2S
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
stx635.pdf
Description
PDF editoriale
Size
711.1 KB
Format
Adobe PDF
Checksum (MD5)
15701e8dc906439bd9699cd3f49623ee